Cutaneous circulation during dehydration and heat stress

1965 ◽  
Vol 20 (2) ◽  
pp. 278-282 ◽  
Author(s):  
Leo C. Senay ◽  
Margaret L. Christensen

Resting subjects were exposed for 12 hr to 43 C dry bulb, 28 C wet bulb, with and without rehydration. During dehydration, average weighted cutaneous opacity pulse amplitudes decreased 19.5%. An apparent relationship between calculated stroke volume and cutaneous pulse amplitudes existed. A 26% increase in heart rate offset decreases in perfusion per beat and probably contributed to a rise in diastolic pressure. Increases in skin temperature paralleled those of oral temperatures. In most subjects evaporative rates were slightly lower during dehydration. Certain dehydrating subjects maintained sweat rates at control levels but this did not prevent an increase in both oral and skin temperatures. Failure of temperature regulation in these experiments does not appear to be due to a decrease in heat transport or evaporation but rather to a lack of responsiveness of the sudomotor and vasomotor systems to increases in body temperature. Reasons for the temperature rise appear complex. evaporative weight loss; heat transport; skin temperature; temperature regulation Submitted on July 22, 1964

1961 ◽  
Vol 16 (1) ◽  
pp. 133-140 ◽  
Author(s):  
L. Brouha ◽  
P. E. Smith ◽  
R. De Lanne ◽  
M. E. Maxfield

Men and women performing a standard exercise were studied in three environments. Pulmonary ventilation, O2 consumption, CO2 elimination, heart rate, blood pressure, body temperature and weight loss were recorded. Pulmonary ventilation was usually decreased in the warm-dry environment and increased in the warm-humid. Oxygen consumption was significantly lower in the warm-dry environment than at room temperature. The pattern of changes of these two functions was similar for both sexes. Respiratory exchange ratios were not influenced by sex, but were higher in the warm-dry environment. Increase in body temperature was found only in the warm-humid environment, with a smaller weight loss than in warm-dry conditions. Systolic blood pressure was influenced by work load but not by environments. Diastolic pressure varied little for both sexes under all conditions. Heart rate was significantly influenced by sex and environment, being highest for the women in the warm-humid conditions. Cardiac cost increased and cardiac efficiency decreased in both warm surroundings, more so for women than for men. Submitted on May 16, 1960


2012 ◽  
Vol 47 (2) ◽  
pp. 184-190 ◽  
Author(s):  
Masaki Iguchi ◽  
Andrew E. Littmann ◽  
Shuo-Hsiu Chang ◽  
Lydia A. Wester ◽  
Jane S. Knipper ◽  
...  

Context: Conditions such as osteoarthritis, obesity, and spinal cord injury limit the ability of patients to exercise, preventing them from experiencing many well-documented physiologic stressors. Recent evidence indicates that some of these stressors might derive from exercise-induced body temperature increases. Objective: To determine whether whole-body heat stress without exercise triggers cardiovascular, hormonal, and extra-cellular protein responses of exercise. Design: Randomized controlled trial. Setting: University research laboratory. Patients or Other Participants: Twenty-five young, healthy adults (13 men, 12 women; age = 22.1 ± 2.4 years, height = 175.2 ± 11.6 cm, mass = 69.4 ± 14.8 kg, body mass index = 22.6 ± 4.0) volunteered. Intervention(s): Participants sat in a heat stress chamber with heat (73°C) and without heat (26°C) stress for 30 minutes on separate days. We obtained blood samples from a subset of 13 participants (7 men, 6 women) before and after exposure to heat stress. Main Outcome Measure(s): Extracellular heat shock protein (HSP72) and catecholamine plasma concentration, heart rate, blood pressure, and heat perception. Results: After 30 minutes of heat stress, body temperature measured via rectal sensor increased by 0.8°C. Heart rate increased linearly to 131.4 ± 22.4 beats per minute (F6,24 = 186, P < .001) and systolic and diastolic blood pressure decreased by 16 mm Hg (F6,24 = 10.1, P < .001) and 5 mm Hg (F6,24 = 5.4, P < .001), respectively. Norepinephrine (F1,12 = 12.1, P = .004) and prolactin (F1,12 = 30.2, P < .001) increased in the plasma (58% and 285%, respectively) (P < .05). The HSP72 (F1,12 = 44.7, P < .001) level increased with heat stress by 48.7% ± 53.9%. No cardiovascular or blood variables showed changes during the control trials (quiet sitting in the heat chamber with no heat stress), resulting in differences between heat and control trials. Conclusions: We found that whole-body heat stress triggers some of the physiologic responses observed with exercise. Future studies are necessary to investigate whether carefully prescribed heat stress constitutes a method to augment or supplement exercise.


Author(s):  
Pooja Devi ◽  
Mahendra Singh ◽  
Yallappa M. Somagond ◽  
A.K. Roy

Background: Heat stress causes oxidative stress and declines milk production potential of cows. The physiological responses and skin temperature of heat stressed animals are good indices for deterring the heat stress. The efficacy of medicinal herb Chlorophytum borivilianum (CB) was tested in lowering the rise in values of physiological responses and skin temperature in crossbred vis a vis Indigenous cows. Methods: Eighteen Tharparkar (TP) and Crossbred KF cows in mid-lactation were given; No supplement (control), a low (T1, n=6) and a high dose (T2, n=6) of CB @ 40 and 80 mg/kg BW/day, respectively for 90 days during hot-humid season. Respiration rate (RR), pulse rate (PR), rectal temperature (RT) and skin temperature (ST) was recorded at the site of forehead, neck, rear body, and udder surface in the morning and afternoon at weekly intervals. Temperature-humidity index (THI) was calculated to assess the degree of thermal stress in animals. Result: Physiological responses and skin temperatures were higher (p less than 0.01) in the afternoon than morning intervals in TP and KF cows. CB feeding significantly lowered physiological responses and ST (p less than 0.01) in high dose as compared to low dose. It was concluded that CB feeding @ 80 mg/kg BW/day effectively alleviates the heat stress. Indigenous cows were found more heat tolerant in comparison to crossbred cows.


Author(s):  
Nima Ahmadi ◽  
Farzan Sasangohar ◽  
Tariq Nisar ◽  
Valerie Danesh ◽  
Ethan Larsen ◽  
...  

Objective To identify physiological correlates to stress in intensive care unit nurses. Background Most research on stress correlates are done in laboratory environments; naturalistic investigation of stress remains a general gap. Method Electrodermal activity, heart rate, and skin temperatures were recorded continuously for 12-hr nursing shifts (23 participants) using a wrist-worn wearable technology (Empatica E4). Results Positive correlations included stress and heart rate (ρ = .35, p < .001), stress and skin temperature (ρ = .49, p < .05), and heart rate and skin temperatures (ρ = .54, p = .0008). Discussion The presence and direction of some correlations found in this study differ from those anticipated from prior literature, illustrating the importance of complementing laboratory research with naturalistic studies. Further work is warranted to recognize nursing activities associated with a high level of stress and the underlying reasons associated with changes in physiological responses. Application Heart rate and skin temperature may be used for real-time detection of stress, but more work is needed to validate such surrogate measures.


1984 ◽  
Vol 57 (6) ◽  
pp. 1738-1741 ◽  
Author(s):  
T. G. Waldrop ◽  
D. E. Millhorn ◽  
F. L. Eldridge ◽  
L. E. Klingler

Respiratory responses to increased skin temperatures were recorded in anesthetized cerebrate and in unanesthetized decerebrate cats. All were vagotomized, glomectomized, and paralyzed. Core body temperature and end-tidal Pco2 were kept constant with servoncontrollers. Stimulation of cutaneous nociceptors by heating the skin to 46 degrees C caused respiration to increase in both cerebrate and decerebrate cats. An even larger facilitation of respiration occurred when the skin temperature was elevated to 51 degrees C. However, respiration did not increase in either group of cats when the skin was heated to 41 degrees C to activate cutaneous warm receptors. The phenomenon of sensitization of nociceptors was observed. Spinal transection prevented all the respiratory responses to cutaneous heating. We conclude that noxious, but not nonnoxious, increases in skin temperature cause increases in respiratory output.


2017 ◽  
Vol 12 (5) ◽  
pp. 662-667 ◽  
Author(s):  
Matthijs T.W. Veltmeijer ◽  
Dineke Veeneman ◽  
Coen C.C.W. Bongers ◽  
Mihai G. Netea ◽  
Jos W. van der Meer ◽  
...  

Purpose:Exercise increases core body temperature (TC) due to metabolic heat production. However, the exercise-induced release of inflammatory cytokines including interleukin-6 (IL-6) may also contribute to the rise in TC by increasing the hypothalamic temperature set point. This study investigated whether the exercise-induced increase in TC is partly caused by an altered hypothalamic temperature set point.Methods:Fifteen healthy, active men age 36 ± 14 y were recruited. Subjects performed submaximal treadmill exercise in 3 randomized test conditions: (1) 400 mg ibuprofen and 1000 mg acetaminophen (IBU/APAP), (2) 1000 mg acetaminophen (APAP), and (3) a control condition (CTRL). Acetaminophen and ibuprofen were used to block the effect of IL-6 at a central and peripheral level, respectively. TC, skin temperature, and heart rate were measured continuously during the submaximal exercise tests.Results:Baseline values of TC, skin temperature, and heart rate did not differ across conditions. Serum IL-6 concentrations increased in all 3 conditions. A significantly lower peak TC was observed in IBU/APAP (38.8°C ± 0.4°C) vs CTRL (39.2°C ± 0.5°C, P = .02) but not in APAP (38.9°C ± 0.4°C) vs CTRL. Similarly, a lower ΔTC was observed in IBU/APAP (1.7°C ± 0.3°C) vs CTRL (2.0°C ± 0.5°C, P < .02) but not in APAP (1.7°C ± 0.5°C) vs CTRL. No differences were observed in skin temperature and heart-rate responses across conditions.Conclusions:The combined administration of acetaminophen and ibuprofen resulted in an attenuated increase in TC during exercise compared with a CTRL. This observation suggests that a prostaglandin-E2-induced elevated hypothalamic temperature set point may contribute to the exercise-induced rise in TC.


Author(s):  
Pongsit Boonruksa ◽  
Thatkhwan Maturachon ◽  
Pornpimol Kongtip ◽  
Susan Woskie

Prolonged or intense exposure to heat can lead to a range of health effects. This study investigated heat exposure and heat-related symptoms which sugarcane workers (90 sugarcane cutters and 93 factory workers) experienced during a harvesting season in Thailand. During the hottest month of harvesting season, wet bulb globe temperature was collected in the work environment, and workloads observed, to assess heat stress. Urine samples for dehydration test, blood pressure, heart rate, and body temperature were measured pre- and post-shift to measure heat strain. Fluid intake and heat-related symptoms which subjects had experienced during the harvesting season were gathered via interviews at the end of the season. From the results, sugarcane cutters showed high risk for heat stress and strain, unlike factory workers who had low risk based on the American Conference of Governmental Industrial Hygiene (ACGIH) threshold limit values (TLVs) for heat stress. Dehydration was observed among sugarcane cutters and significant physiological changes including heart rate, body temperature, and systolic blood pressure occurred across the work shift. Significantly more sugarcane cutters reported experiencing heat-related symptoms including weakness/fatigue, heavy sweating, headache, rash, muscle cramp, dry mouth, dizziness, fever, dry/cracking skin, and swelling, compared to sugarcane factory workers. We conclude that the heat stress experienced by sugarcane cutters working in extremely hot environments, with high workloads, is associated with acute health effects. Preventive and control measures for heat stress are needed to reduce the risk of heat strain.


1965 ◽  
Vol 20 (1) ◽  
pp. 31-36 ◽  
Author(s):  
C. H. Wyndham

The response characteristics have been studied of the curves relating heat conductance and sweat rate to change in rectal temperature at different levels of skin temperature, and vice versa. The increase in these responses with deviation in rectal temperature from the “neutral” setting is highly nonlinear; the neutral point and the curve shift to the right and the slope decreases with lowering of skin temperature and vice versa when it is raised. With further deviation of rectal temperature these responses reach maximum values, i.e., become “saturated.” All of these features are analogous to servomechanisms with negative feedback, giving sensitive and stable control. Control of these responses by skin temperature is more linear, characterizing passive control systems which are insensitive and less stable. Quantitatively, the effect at skin temperature of 26 C of 1 C rise in rectal temperature on heat conductance and sweat rate is 10 times greater than the same rise in skin temperature; at a neutral skin temperature of 33–34 C, a rise of 1 C in rectal temperature is 6–7 times greater; at a high skin temperature of 36 C, a rise in rectal temperature of 1 C is 4–5 times greater. relationship between heat conductance and a change in either rectal or skin temperatures; relationship between sweat rate and a change in either rectal or skin temperatures; response characteristics of curves relating heat conductance to change in either rectal or skin temperatures; response characteristics of curves relating sweat rate to change in either rectal or skin temperatures; assessment of the contribution of skin and rectal temperatures to man's temperature regulation Submitted on October 22, 1963


1981 ◽  
Vol 25 (1) ◽  
pp. 774-778
Author(s):  
Alex Loewenthal ◽  
David J. Cochran ◽  
Michael W. Riley

Nine fully acclimatized men falling in the lean, medium and obese categories of body composition were observed during heat exposure periods for four days following acclimatization decay periods of various lengths in order to determine the effects of body composition on the decay and reinduction of acclimatization. The physiological variables taken into consideration were core temperature, “DuBois” mean skin temperature, heart rate, weight loss due to perspiration and the temperature differential between the core and surface. All of the men were subjected to an acclimatization schedule of twelve daily sessions in order to insure that they were all fully acclimatized. Three decay, or non-exposure, periods of four, eight and twelve days were each followed by four days of reinduction. It was determined that body composition does not affect the rate of decay or reinduction of acclimatization, although this parameter as well as the extent of decay and the duration of the reinduction period does affect the physiological variables monitored in this study.


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